In general, the picture quality failures or picture noises of so-called dynamic false contour is likely to be perceived in moving images shown on image display devices such as PDP or the like that utilizes the sub-field (SF) to display grayscales. Dynamic false contour occurs as a result of a discontinuous lighting pattern transition of SFs compound with the desired continuous lighting pattern of grayscales. Increasing the number of SFs contained within a field is known to improve the dynamic false contour. However, the increased number of SFs will reduce the period of time of lighting causing and undesirable brightness level.
To solve the problem, an example is disclosed to restrict the combinations of SFs in a moving image area, limiting the increase of SFs within not so many numbers, to suppress the dynamic false contour (for example, see Japanese Patent Unexamined Publication No. 2000-276100). Conventional display devices are capable of reducing dynamic false contour in the moving image area by restricting the combination of grayscales. However, this reduction of the number of grayscales degrades picture quality because false grayscales are created by the dithering process for the purpose of maintaing a certain overall level of grayscale. Accordingly, the additional grayscales created by the dithering process as an attempt to reduce dynamic false contours causes a degradation in picture quality,
To solve this problem, the present invention aims to provide an image display device capable of suppressing the dynamic false contour while maintaining a good grayscale display.